code: def test_empty_graph_hash():
      """
      empty graphs should give hashes regardless of other params
      """
      G1 = nx.empty_graph()
      G2 = nx.empty_graph()
  
      h1 = nx.weisfeiler_lehman_graph_hash(G1)
      h2 = nx.weisfeiler_lehman_graph_hash(G2)
      h3 = nx.weisfeiler_lehman_graph_hash(G2, edge_attr="edge_attr1")
      h4 = nx.weisfeiler_lehman_graph_hash(G2, node_attr="node_attr1")
      h5 = nx.weisfeiler_lehman_graph_hash(
          G2, edge_attr="edge_attr1", node_attr="node_attr1"
      )
      h6 = nx.weisfeiler_lehman_graph_hash(G2, iterations=10)
  
      assert h1 == h2
      assert h1 == h3
      assert h1 == h4
      assert h1 == h5
      assert h1 == h6
  
imports: import pytest
  import networkx
  from networkx.generators import directed
label_desc: Use image node_id 1 for calling a global function with example usage: test_empty_graph_hash() without return types